1. Field of the Invention
The present general inventive concept relates to an interface device, and more particularly to an interface device to control data transfer between chips.
2. Description of the Related Art
Recently, system-on-chips have been employed in various portable devices. In the portable devices, a scheme to reduce power consumption is preferably implemented so that the operating time of the portable devices can be extended. When the interface device employs complementary metal oxide semiconductor (CMOS), the interface device conducts current in response to bit state toggling of the outputs. Therefore, reducing a bit toggle rate can decrease the amount of power consumed at the CMOS outputs.
The toggle rate is determined as the rate at which each value of the present data and the previous data changes state. When data are transmitted without being processed, the toggle rate is not controlled. In the worst case, where each bit of the present data is in a different state as the same bit in the previous data, the toggle rate is substantially 100% and consequently, a large amount of power is consumed.
Accordingly, there is a need to provide a device to reduce the toggle rate, and thereby, to reduce the power consumption of the interface device.